HOW TO OPTIMIZE THE USE OF PHOSPHATE RESOURCES BY PRODUCING ALTERNATIVE TOTALLY ACIDULATED PHOSPHATE FERTILIZERS

Transcription

1 PSP Facing Phosphorus Scarcity HOW TO OPTIMIZE THE USE OF PHOSPHATE RESOURCES BY PRODUCING ALTERNATIVE TOTALLY ACIDULATED PHOSPHATE FERTILIZERS Dr. Luís Ignácio Prochnow IPNI Brazil Program Director APATITE

2 INITIAL CONSIDERATION This presentation challenges researchers and the nutrient stakeholders to think differently regarding P sources.

3 WHAT IS THIS? Is this a mineral? Does it occur in soils? Does it occur in fertilizers?

4 WHAT IS THIS? Is this a mineral? Does it occur in soils? Does it occur in fertilizers?

5 QUESTION/ COMPOUND CHARACTERIZATION Chemical Formula Fe 3 KH 8 (PO 4 ) 6.6H 2 O Fe 3 KH 14 (PO 4 ) 8.4H 2 O Is it a mineral? No No Where does it precipitate? P Fertilizer, Generally in SSP P Fertilizer, Generally in TSP Total P (TP) NAC Soluble P (CSP) Water Soluble P (WSP) (WSP/CSP) * RAE(MCP; Upland Rice) RAE (MCP; Flooded Rice) Both compounds are much avoided by the P fertilizer industry because of their low water solubility. Does science prove this to be always necessary?

6 BACKGROUND INFORMATION Totally acidulated P fertilizers (SSP, TSP, MAP, DAP) have high water solubility (WSP). Premium Grade PR to produce such fertilizers is decreasing worldwide. High amounts of energy and money are spent in order to always produce P fertilizers with high contents of WSP. To produce high WSP P sources part of the apatite concentrates are discarded, which means lost and potential environmental problems. Is it really necessary for totally acidulated P sources (not PAPR) to always have high water solubility? Interest and momentum exist to consider maybe such requirement is not necessary, leading to a better use of PR?

7 STUDY 1 Characterization and agronomic evaluation of single superphosphates varying in iron phosphate impurities N. Compound SSP1 SSP2 SSP3 1 Fe3KH8(PO4) Fe3NaH8(PO4) Fe3H9(PO4) Na2SiF Ca10(PO4)6OH0.97F Ca4SiAISO4F SiO CaF MgSO SrSO ZnSO Ti2(SO4) BaSO Al2(SO4) Ba(H2PO4) CaSO Ca(H2PO4) TOTAL P Source P Fe fi Total Available Water 2% C.A. % MCP SSP SSP SSP % of WSP P Source Dry-matter yield P uptake Upland Rice MCP SSP SSP SSP Flooded Rice MCP SSP SSP SSP mcp: Standard source of P RAE = (bi/bmcp)*100, i = other SSP Source: PROCHNOW, L.I.; CHIEN, S.H.; TAYLOR, R.W.; CARMONA, G.; HENAO, J. & DILLARD, E.F. Agronomy Journal. 95: , 2003.

8 STUDY 2 Plant Availability of Phosphorus in Four Superphosphate Fertilizers Varying in Water-Insoluble Phosphate Compounds Fonte de P a ph Modelo de regressão segmentada Equação quadrática (R 2 ) SE d Plateau Plateau Dose (mg kg- 1 P) requirida para alcançar b 90% do plateau WSP (%) requerido para alcançar c Plateau 90% do plateau mg P kg % MCP-DMY 5,2 y = 0,94 + 0,957x 8,8 x 10-3 x 2 (0,98) 1,25 26,9 54,3 36,8 MCP-RY 5,2 y = 3,27 + 3,337x 30,0 x 10-3 x 2 (0,97) 4,37 93,9 54,3 36,8 MCP-DMY 6,4 y = 0,70 + 1,447x 19,3 x 10-3 x 2 (0,97) 1,45 27,8 37,4 25,4 MCP-RY 6,4 y = 2,44 + 5,047x 67,4 x 10-3 x 2 (0,95) 5,05 96,9 37,4 25,4 TSP 1-RY 5,2 y = 35,44 + 1,249x 7,9 x 10-3 x 2 (0,97) 1,57 84, TSP 1-RY 6,4 y = 34,13 + 1,830x 15,3 x 10-3 x 2 (0,96) 2,66 88, TSP 2-RY 5,2 y = 47,98 + 0,745x 3,9 x 10-3 x 2 (0,97) 2,14 83, TSP 2-RY 6,4 y = 42,97 + 1,161x 6,8 x 10-3 x 2 (0,96) 5,04 92, SSP 1-RY 5,2 y = 17,93 + 1,705x 11,4 x 10-3 x 2 (0,97) 3,62 81, SSP 1-RY 6,4 y = 24,42 + 1,897x 13,1 x 10-3 x 2 (0,97) 2,21 93, SSP 2-RY 5,2 y = 58,76 + 0,683x 4,7 x 10-3 x 2 (0,96) 4,02 83, SSP 2-RY 6,4 y = 60,97 + 0,926x 6,9 x 10-3 x 2 (0,95) 5,24 92, Source: PROCHNOW, L.I.; CHIEN, S.H.; CARMONA, G.; HENAO, J.; DILLARD, E.F.; AUSTIN, E.R. Soil Science Society of America Journal, 72: , 2008.

9 Intensity(Counts) STUDY 3 Synthesis, characterization and agronomic evaluation of iron phosphate impurities in superphosphates SEM Fe 3 KH 8 (PO 4 ) 6.6H 2 O 85.4 IR Fe 3 KH 14 (PO 4 ) 8.4H 2 O %T cm X-ray Chemical Analysis for total P, Fe, K, S and water of hydration Análise química para P total, Fe, K, S e água de hidratação KFe3H8(PO4)6! 6H2O - Potassium Iron Hydrogen Phosphate Hydrate Theta( ) Calculated Formula: Fe 2.8 K 1.1 H 8 (PO 4 ) 6!6.1H 2 O Fórmula calculada: Fe 3.0 K 0.9 H 14 (PO 4 ) H 2 O Source: PROCHNOW, L.I.; CHIEN, S.H.; et al. Soil Science Society of America Journal. 67: , 2003.

10 STUDY 3 Synthesis, characterization and agronomic evaluation of iron phosphate impurities in superphosphates P Source Crop Segmented Regression Model WSP (%) required to reach Quadratic Equation SE Plateau Plateau 90% of Plateau H8-syn Upland Rice Y= X-6.2x10-3 X H14-syn Upland Rice Y= X-2.8x10-3 X H8-syn Flooded Rice Y= X-20.0x10-3 X H14-syn Flooded Rice Y= X-3.8x10-3 X Standard error for comparing predicted values. Percentage water-soluble P needed to obtain the plateau or 90% of the plateau of the segmented model. Source: PROCHNOW, L.I.; CHIEN, S.H.; et al. Soil Science Society of America Journal. 67: , 2003.

11 DOESN T IT SOUND FUNNY? The fertilizer industry spends energy and money to transform phosphate rock, which has very low water solubility, in highly soluble P sources, like SSP, TSP, MAP, DAP, and then, because it is too soluble, many try to somehow protect it for lower water solubility? Isn t there another possibility? Isn t there a more logical possibility?

12 WHAT IS THE PRACTICAL MEANING OF HAVING TOTALLY ACIDULATED P FERTILIZERS WITH LOWER WSP BUT WITH HIGH AGRONOMIC EFFECTIVENES? Decrease in disposal of part of certain P resources. Lower WSP sources = lower potential environmental problems. Higher efficiency. Optimization in the use of P Resources. Anyone interested?

13 Statistical Group Experiment Analysis - 16 Field Experiments - Treatment P SOURCE AVERAGE RAE 1 SSP GCA (High WSP) 96.1 A 2 SSP RCA (Low WSP) 95.3 A 3 SSP GCA/RCA 94.5 A 4 SSP Patos (Low WSP) 95.5 A Source: PROCHNOW, L.I. Unpublished. Scientific Report.

14 GENERAL CONCLUSIONS Research has showed not to be necessary to always have high water-solubility in fully acidulated phosphate fertilizers. Data obtained indicated that the WSP requirement should be related to the soil system, the crop and the chemical composition of the fertilizer. Some Fe-P compounds, now avoided by the industry, can be good sources of P in some circuntances and can be agronomically more effective as a source of P under flooded soil systems than for upland crop systems. This all translates into possibilities for specific sources for different agro-climatic conditions, with a better use of P Resources.

15 Lehr (1980) Are water-insoluble phosphates to be avoided at all cost? The need for a more realistic set of product specifications is one of the most important problems confronting phosphate producers to seek relief from unnecessary and costly purification steps. Only agronomic research can provide the necessary guidance.

16 QUESTION Some have been repeating the same message, now with more data, that Lehr stated decades ago. Why no action to optimize the use of PRs by producing alternative totally acidulated P fertilizers with lower water solubility? No credibility. More studies needed. People resist to change. I invite you to think about this possibility

17 THANKS FOR YOUR IPNIBrasil Website: Telephone/fax: 55 (19)